Throat-plate for sewing-machines.



. P" ri rue,"

Specification of Letters Patent.

Patented llliay 251i,

Application filed Jury 20, 1915. Serial No. Il.

To all whom 'it may concern:

Be 1t known that I, CHESTER McNair., a

vcitizen of the United States, residing at description, reference being had to the accompanying drawing and to the figures of reference marked thereon. A

-The invention relates .to new and useful improvements in throat plates for sewing machines, and more particularly to a throat plate adapted to be used in connection with a stitching mechanism for forming a flat seam.

An object of the invention is to provide a throat plate having an opening in which the needles of stitch-'forming mechanisms located one in advance ofthe other, operate with stitch tongues which project into said opening and across which the cross threads ot'. the stitching mechanisms are laid. respectively, the free ends of said stitch tongues terminating in substantially the same line, whereby the cross threads of the front stitching mechanism will be supported until the cross threads of the rear stitching mechanism are laid.

1n the drawings,

Figure 1 isa plan view of a throat plate embodying my improvements;

y Fig. 2 is a plan View of the end of a worksupporting arm having my improved throat plate thereon, and also shwing the feed dog coperating with the throat plate;

Fig. 3 is a plan View 'showing the worksupporting a rm and a presser 'foot which cooperates with the throat plate;

Fig. 4 is a view partly in vertical section l and partly in side elevation, showing the throat plate, the feed dog, the presser foot and the needles which cooperate therewith,

Fig. 5 is a plan view showing a slightly modified form of a throat plate;

Fig. 6 is a sectional view on the line 6-6 of Fig. 5.

. Fig. 7 is a detail showing more or less diagrammatically in bottom plan view a seam stitched on my improved throat plate.

l have shown my improved throat plate 1 as securedto the free end of a cylindrical work4 support 2. The throat plate is secured thereto by suitable screws 3, 3. Said throat plate is formed with parallel openings el. and 5, which are spaced from each other and receive the outer webs oi the feed dog 6. Vlhe throat plate is also provided with openings 7 and 8, which receive other webs of the feed' dog. The tln'oat plate is i'urther provided with an opening 9, adapted to re ceive the needles 10, 10 and 11, l1.

er looper 12 cooperates with the needles 10, 10, beneath the work support, and suitable cross thread-laying mechanism (noty shown) cooperates with these needles above the work support. rlhis forms one of the stitching mechanisms for which the throat plate is especially adapted. t lcoper 13 cooperates with the needles 1l, 11 and suitable cross thread-laying mechanism (not shown) coperates with these needles above the work support and forms the other stitchinginechanism, for which the throat plate is esjiecially adapted. lt will be noted that these stitch-forming mechanisms which are independent ot each other, are located one in rear of the other.

lThe needles 11, "il, are, however, staggered relative to the needles 10, 10, so that one needle ol' each pair is in a line passing centrally between the needles oil' the other pair and parallel with the line of feed.

The presser Jfoot 101 engages the throat plate and has suitable openings 'for the needles 10-1O and also the needles 11-11, as clearly shown in l? The throat plate is formed with a stitch tongue 1l, which extends rearwardly between the needles 10, l0, into the opening 9. Said throat plate is also formed with. a stitch tongue '15, which extends rearwardly be l tween the needles 11, 11 into the opening The stitch tongue 14.- is formed hy the slots 16, 16, which lead from the needle openings rearwardly to the end et' the stitch tongue. The stitch tongue 15 is itormed by the slots 1T, 17, which likewise extend from the needle openings for the needles 11, 11 rearwardly to the end of the stitch tongue. lt will be noted that the inner slot 16 is between the 'slots 17,17, 'while the inner slot 17 is be'vv 'tween the slots 16, 1G and vin the tongue 14. lt will also be noted that the free ends of the stitch tongues le and 15 terminate substantially in the same line. ln the formaion of the stitches, the looper thread of the looper 12 will be laid across the stitch tongue 14e, while the looper thread ot the -looper 13 will be laid across the Istitch tongue A15.

. nisros.' looper thread laid across the Winch enchsined by the inner needle'of the roer pen" or needles, will be leid. also lengthwise of the seam across the looper *l eds of' the iront stitching mechanism. the time these loops are laid and drawn, the looper thread of the front stitching mechanism is ecross the stitch tongue .14, and, therefore, .l ein chie to foi-'ni s very elastic seein,- or one in which the threads .not dren the fabric so es to'prevein the icrinlng oi o normal/ly Het see-m.

"in nlug'. 5 of the dreivn'igs. l have shown n.1 3, l niotuned torni ori-tie invention. T e throat plete. 1' hes the feed slots fl, 5, 7 and :ilse the opening 9 for the needles .ce of the integral stitch tongues dehed, l here pr vided three stitch tongues i9 9.0. `rlhese stitch tongues are set L' v ooi/es in the throat plete, and are rein foy suitable screws 22. This l l the stitch tongues to he readily removed if hrolien and replaced. Oneof the needles 10 Vpssses niong the outer fece of the stitch. tongue while the other needle 10 passes between t'e stitcl'irtongues 18 and 19, .indicated in Fig. 5. The outer needl'ell of the reni' .pnir oi? needies passes alongside ofthe outer face orr the stitch tongue 18, While the other needle passes between the stitch tongues fend 20, as is also indicated in lig. 5.

From the shove it will he apparent that the stitch tongnes and 19 combine to forni e. singie stitch tongue for the rear pair of needles, while the' stitch tongues '19 and 2.0 combine to -orm e. stitch tongue for the front peir oi needles. The free ends of these stitch tongues terminate 1n substan- ,tisily saine' line es shove descrihedend accomplish the saine purpose.

ln Fig. i', l have shown more or less diagrsinmnticelly e bottom plan View ofv e seam stitch 'tongue 1&5: will he held hy this stitch Whit,L nre arranged as described above. In v Leccese 4erating with the needles 10-1O is indicated at Z; the threads oi the needles 11-11 nre indicated et n-n, and the thread of the looper 13 which cooperates with the needles 11`11 is indicated at l.

It is obvious that minor changes in the details of construction :ind thl :urzimgemcnt of parts may he unido, without departing from the spiritof the invention :is set vlorth in the appended claims.

Having thus described my invention, what l clniln as new and desire to secure h v Letters Patent, is

l. A throat plate haring :in opening adapted to receive two pairs ot needles, one of which is arranged in rear of the other and olset relative thereto, said throat plete haring stitch tongues extending; into seid opening, the stitch tongue for the front pnir of needles being extended to n point in rear of the rear pnir of needles, said stitch tongue igor the front psir of needles havingr :i portion thereof in common with the stitch tongue of the rear pair of needles.

2. A plate having :1n opening adapted to receive two pairs of needles, one ol which is arranged in reni' of the other und ol'Y'sot relative thereto, said plate having; stitch tongues` exto/ruling,r into said opening, one of said stitch tongues having n thread slot for one of the needles of one pnir :1nd the other stitch tongue having n thread slot 'for one of 'the needles of the other pair.

3. The combination o1 :i plate having', n needle opening therein, pairs of needles nrranged one in rear ci' the other und stugggered relative to euch other, three fingers carried by said piste sind projecting' into said needle opening, the central linger ero tending between the needles of each pair, the other fingers extending res'pectivch,T hetween one pair of vneedles and outside of the other pair of needles, and :1li of seid fingers terminating inl rear of the' rear pair of needles.

In testimony whereof, l: nilix signnture in the presence of two Witnesses.

CHESTER LileNElfL. Witnesses S. Gnomes TArn, A. F. BnnDsHALL. 

